I've had the exact same issue on the exact same router (RT-AX86U) with the exact same firmware (386.7_2). To this day I haven't figured out what is causing it. I have no HD attached to it and AIProtection is disabled, so those are definitely not the issue, for me at least.
In fact I have 2...
Well I had the log open when connecting to VPN and that error would log just after VPN got connected. It happened each time so unless it was a huge coincidence I assume it was the VPN initiating the error log. Also the redacted IP is the router IP and the MAC is the VPN MAC address, so I think...
Yes.
Since you mentionned the AIProtection, I was wondering if something was fishy on that front. I enabled AIProtection then immediately disabled it again. I then tried connecting to my VPN servers and I am not seeing these errors anymore. So I enabled AIProtection again and left it enabled...
I recently upgraded to Merlin 386.7_2. I am seeing the following logs. It could be they were here before but only noticed them recently.
Nov 7 17:53:57 kernel: *** ERROR: [send_redir_page:614] # redir_url=http://[REDACTED IP:XX]/blocking.asp?cat_id=94&mac=[REDACTED MAC]&domain=ptaimpeerte.com...